The present invention relates to a spot-type disc brake in general, and more particularly to a disc brake for automotive vehicles.
It is customary to provide a disc brake of this type with a brake caliper which embraces the periphery of a brake disc as well as with brake shoes that are supported on a brake support member on both sides of the brake disc. The caliper usually carries a brakeactuating device. In many disc brake constructions, the brake caliper is positively connected to the brake support member by means of a guide element that is in sliding engagement with a portion of the brake support member to permit the caliper to move in the direction of the axis of rotation of the brake disc.
In a known spot-type disc brake of the above type, which is disclosed in German printed and published patent application No. 28 36 589, the brake caliper is rigidly coupled to the guide element and the latter is slidably supported on the disc entry side in a bore of the brake support member. This provides for an exact alignment of the brake caliper relative to the brake disc. A second guide element is slidably supported at the disc exit side in a bore of the brake support member in parallel to the first-mentioned guide element. The second guide element has at its fastening end a transverse bore lined with elastic material. A pin of the brake caliper extending in a circumferential direction of the brake disc engages in this transverse bore. Due to this design, transverse forces in the caliper guidance are avoided to a large degree in the known spot-type disc brake when the brake support member deforms under load. However, the movement of the brake shoes in the direction of rotation of the brake disc during braking leads to a considerable clamping of the first guide element in its supporting bore and thereby impairs ease of slidability of the brake caliper in relation to the brake support member. As a result, the first guide element is subject to increased wear. In addition, there occur movements due to deformation at the brake caliper as a result of this arrangement which cause wedge-shaped wear of the brake shoes, as viewed in the circumferential direction of the brake disc.